The invention is directed to a multi layer film that can be used as a flexible packaging material for enclosing and containing one or more compressible products in a sealed condition. The invention is also directed to the package containing products in a compressed condition comprising the multilayer film according to the present invention.
Companies as well as consumers pay more and more attention to environmental and sustainability aspects of packaging (see e.g. Challenges to Packaging in a global world, Gunilla Jonson, Marcus Wallenberg Prize symposium, Sep. 30, 2005 and Marsh, Food Packaging, Journal of Food Science, Vol. 72, 3, 2007, pages 39-55). Using lower amounts of raw materials, reducing costs and developing additional packaging functionalities have become important goals for research and development. When it comes to packaging there appear to be a lot of theoretically options to improve sustainability such as for example using thinner layers of different materials, using less material by changing the shape of the package, using recycled material and using refillable packages. However these solutions often do not result in a packaging that fulfils the requirements for providing a good protection to the packaged products.
The key to successful packaging is to select the packaging material and design that best fulfils technical and commercial requirements with regard to product characteristics, marketing considerations, environmental issues and cost. Not only is balancing so many factors difficult but also it requires a different analysis for each product.
There exist many packaging techniques such as for example compression packaging wherein product is compressed while being packaged to reduce its volume. Compression packaging may be used for packaging of for example insulation materials (EP 908400 A1), absorbent articles such as diapers (EP 747295 A1 and EP 1795161 A1) as well as textile articles and straw.
Packaging techniques have been developed for providing a package comprising for example a number of flexible diaper bags. WO 03/055773 discloses that when transporting finished products from the point of manufacture to the point of sale, or to an intermediate storage facility, it is often desirable to enclose a plurality of products within a larger, more durable package. Not only does this preserve the products in their desired, saleable condition, it minimizes the number of individual items to be handled and generally provides more uniformly shaped items for stacking and handling. Products often shipped in a compressed condition are disposable absorbent products for example disposable diapers can be highly compressed and packaged to minimize shipping and storage space requirements. Also WO 98/24711 discloses a package for efficiently packaging and shipping compressible products, and a method for producing such a package.
During transport it is essential to have the guarantee of an excellent sealing between the several parts of the flexible package. Sealing of the film end flaps can be done by using sealing equipment such as a compression packaging machine as for example disclosed in U.S. Pat. No. 3,753,331.
Polymers have many applications in the packaging industry and the polymers which are potential suitable are countless and in film extrusion these polymers may be used as a single or as a multilayer structure. JP2002273843 discloses a polyethylene based film for compression packaging consisting of three layers. The first and the second layer of the three layers are an ethylene-alpha olefin copolymer and the third layer is a low density polyethylene.